This invention relates generally to gas turbine engines, and more particularly, to methods for fabricating combustors used with gas turbine engines.
A turbine engine includes a compressor for compressing air which is mixed with a fuel and channeled to a combustor wherein the mixture is ignited within a combustion chamber for generating hot combustion gases. At least some known combustors include a dome assembly, a cowling, and liners to channel the combustion gases to a turbine, which extracts energy from the combustion gases for powering the compressor, as well as producing useful work to propel an aircraft in flight or to power a load, such as an electrical generator. The liners are coupled to the dome assembly with the cowling, and extend downstream from the cowling to define the combustion chamber. At an aft end of the combustion chamber, the liners are coupled to a turbine nozzle by a mounting flange.
At least some known liners include a plurality of panels that are connected together with riveted, bolted, or welded connections. More specifically, within at least some known combustors, the liners are coupled together in series such that adjacent liners form an over hang portion of the liners. During assembly of the liners, it is known to use a spatter shield fabricated from copper to facilitate preventing secondary welding of the liner panels when the mounting flange is coupled to the liners. More specifically, at least some known spatter shields are fabricated from copper.
However, when electron beam welding is used to couple cobalt base alloys, the copper spatter shields may become inadvertently fused to the components being welded. Removing the fused shields from the panels may be a time-consuming process because acid may be required to dissolve the fused copper material from the liner panels. Alternatively, depending upon the amount of material that was fused to the panels, the panels, and/or shield, may be deemed non-salvageable. Furthermore, because of the susceptibility of the copper to fuse, weld cracks and/or weld heat affected zone (HAZ) cracking may occur during welding of the cobalt base alloys.